High-efficiency lawn maintenance tool and high-efficiency cutting blade

ABSTRACT

A high-efficiency blade for a lawn maintenance tool includes a central axis and a mounting portion located on the central axis. The high-efficiency blade includes a cutting blade and a cutting blade sharpened leading edge. A cleaning blade is vertically offset from the cutting blade and is configured to mulch the associated clippings from vegetation and reduce an associated accumulation of clippings on an underside of an associated mower deck. The lawn maintenance tool can also include a deck having a separation distance between the cleaning blade and an underside of the deck. The deck can include an elevation change to vary the separation distance. The deck and high-efficiency blade can also include a forward or rearward tilt.

This application is a continuation of U.S. patent application Ser. No.16/152,440 filed on Oct. 5, 2018 and claims the benefit of U.S.Provisional Application No. 62/569,078, filed Oct. 6, 2017, the entiredisclosure of which is hereby incorporated herein by reference.

FIELD OF THE DISCLOSURE

The present disclosure is directed to a high-efficiency lawn maintenancetool and high-efficiency bladeconfigured to perform a grass cuttingfunction utilizing a reduced amount of energy than a typical lawnmaintenance tool.

BACKGROUND

Typical walk-behind lawn mowers and riding mowers utilize an engine orother power supply to rotate one or more mower blades. The mower bladesare typically formed by stamping a thick metal sheet in order to form anelongated metal blade. These thick, heavy blades rotate at high speeds,which requires significant torque to maintain such high rotationalspeeds of the blade(s). As a result, large engines—typically in the formof a combustion engine—are attached to a mower deck or a mower frame,and these large engines are needed to produce the high torquerequirements for rotating the heavy blades. Thus, improvements aredesired to reduce the noise level of lawn mower power sources andprovide relatively high-efficiency blades to reduce the amount of energyneeded to rotate the blade.

BRIEF SUMMARY

According to one aspect of the present disclosure, a high-efficiencyblade for a lawn maintenance tool includes a central axis and a mountingportion located on the central axis. The high-efficiency blade alsoincludes a cutting blade having at least one segment and a cutting bladesharpened leading edge. The cutting blade sharpened leading edge isgenerally parallel to a driven surface and the cutting blade sharpenedleading edge is configured to cut clippings from vegetation. Thehigh-efficiency blade further includes a cleaning blade. The cleaningblade is vertically offset from the cutting blade and is configured tomulch the associated clippings from vegetation and reduce an associatedaccumulation of clippings on an underside of an associated mower deck.

According to another aspect of the present disclosure, a high-efficiencylawn maintenance tool comprises a frame and a deck. The deck is attachedto the frame and the deck defines a downward facing space. Thehigh-efficiency lawn maintenance tool also includes a high-efficiencyblade located within the downward facing space. The high-efficiencyblade includes a central axis and a mounting portion located on thecentral axis of the high-efficiency blade. The high-efficiency bladealso includes a cutting blade including at least one segment and acutting blade sharpened leading edge. The cutting blade sharpenedleading edge is generally parallel to an associated driven surface andis configured to cut clippings from vegetation. The high-efficiencyblade further includes a cleaning blade that is vertically offset fromthe cutting blade. The high-efficiency lawn maintenance tool furtherincludes a power source that is attached to one of the frame or thedeck. The power source provides rotational power to the high-efficiencyblade. The high-efficiency lawn maintenance tool still further includesa plurality of ground engaging members attached to one of the frame orthe deck. The cleaning blade is configured to follow a rotational pathabout the central axis, and a portion of the cleaning blade is locatedwithin 1-inch to 1/16-inch of the deck over a majority of the rotationalpath. The deck defines an elevation change such that the cleaning bladeis not located within 1-inch to 1/16-inch of the deck over a minority ofthe rotational path of the cleaning blade.

According to another aspect of the present disclosure, a high-efficiencylawn maintenance tool includes a frame and a deck attached to the frame.The deck defines a downward facing space. The high-efficiency lawnmaintenance tool also includes a high-efficiency blade located withinthe downward facing space. The high-efficiency blade includes a centralaxis and a mounting portion located on the central axis of thehigh-efficiency blade. The high-efficiency blade also includes a cuttingblade including at least one segment and a cutting blade sharpenedleading edge. The cutting blade sharpened leading edge is generallyparallel to an associated driven surface and is configured to cutclippings from vegetation. The high-efficiency blade further includes acleaning blade that is vertically offset from the cutting blade. Thehigh-efficiency lawn maintenance tool further includes a power sourcethat is attached to one of the frame or the deck. The power sourceprovides rotational power to the high-efficiency blade. Thehigh-efficiency lawn maintenance tool still further includes a pluralityof ground engaging members attached to one of the frame or the deck. Thedeck and the high-efficiency blade are tilted such that the central axisis not vertical.

Advantages of the present disclosure will become more apparent to thoseskilled in the art from the following description of the embodiments ofthe disclosure which have been shown and described by way ofillustration. As will be realized, the disclosed apparatus are capableof other and different embodiments, and their details are capable ofmodification in various respects.

BRIEF DESCRIPTION OF SEVERAL VIEWS OF THE DRAWINGS

These and other features of the present disclosure, and theiradvantages, are illustrated specifically in embodiments of thedisclosure now to be described, by way of example, with reference to theaccompanying diagrammatic drawings, in which:

FIG. 1 is a perspective view of an example traditional lawn maintenancetool according to at least one embodiment;

FIG. 2 is similar to FIG. 1 , showing a perspective view of ahigh-efficiency lawn maintenance tool;

FIG. 3 is a perspective view of a high-efficiency blade that can be usedin conjunction with the lawn maintenance tools of FIGS. 1 and 2 ;

FIG. 4 is a cross-section view of a cutting blade portion of thehigh-efficiency blade of FIG. 3 ;

FIG. 5 is a cross-section view of a cleaning blade portion of thehigh-efficiency blade of FIG. 3 ;

FIG. 6 is similar to FIG. 3 , showing a high efficiency blade without adownward pointing third segment;

FIG. 7A is a perspective view from a bottom side of anotherhigh-efficiency blade that can be used in conjunction with the lawnmaintenance tools of FIGS. 1 and 2 ;

FIG. 7B is similar to FIG. 7A, viewed from a top side of thehigh-efficiency blade;

FIG. 8 is a cross-section view of a high-efficiency blade attached to amulti-spindle lawn maintenance tool and is taken along line 8-8 of FIG.21 ;

FIG. 9 is a cross-section view of another embodiment of ahigh-efficiency blade that can be used in conjunction with the lawnmaintenance tools of FIGS. 1 and 2 ;

FIG. 10 is an exploded view of a high-efficiency blade system assemblyincluding another embodiment of a high-efficiency blade;

FIG. 11 is a cross-section view of the assembled components of FIG. 10 ;

FIG. 12 is a detail view of a motor mount used in the assembly of FIGS.10 and 11 ;

FIG. 13 is a detail view of a leaf spring used in the assembly of FIGS.10 and 11 ;

FIG. 14 is a schematic view of a lawn mower deck showing an area ofgreater separation distance between the cleaning blade and an undersideof the deck;

FIG. 15 is a cross-section view taken along line 15-15 of FIG. 14showing a typical separation distance between the cleaning blade and thedeck;

FIG. 16 is a cross-section view taken along line 16-16 of FIG. 14showing an increased separation distance between the cleaning blade andthe deck;

FIG. 17 is a cross-section view taken along line 17-17 of FIG. 14showing a transition separation distance between the cleaning blade andthe deck;

FIG. 18 is similar to FIG. 17 and is a cross-section view taken alongline 16-16 of FIG. 14 showing a transition separation distance betweenthe cleaning blade and the deck;

FIG. 19 is an exploded view of a high-efficiency blade assembly for afive-spindle high-efficiency lawn maintenance tool;

FIG. 20 is an exploded view of a drive spindle and drive gear from theassembly of FIG. 19 ;

FIG. 21 is a top view of the five-spindle high-efficiency lawnmaintenance tool of FIG. 19 ;

FIG. 22 is a bottom view of the five-spindle high-efficiency lawnmaintenance tool of FIG. 19 ;

FIG. 23 is a schematic representation of a controller used inconjunction with the high-efficiency lawn maintenance tool;

FIG. 24 is a side view schematic of the high-efficiency lawn maintenancetool showing a rearward tilt of the deck and high-efficiency blade;

FIG. 25 is similar to FIG. 24 , showing a level deck and high-efficiencyblade; and

FIG. 26 is similar to FIG. 24 , showing a frontward tilt of the deck andhigh-efficiency blade.

It should be noted that all the drawings are diagrammatic and not drawnto scale. Relative dimensions and proportions of parts of these figureshave been shown exaggerated or reduced in size for the sake of clarityand convenience in the drawings. The same reference numbers aregenerally used to refer to corresponding or similar features in thedifferent embodiments. Accordingly, the drawing(s) and description areto be regarded as illustrative in nature and not as restrictive.

DETAILED DESCRIPTION

Referring to FIG. 1 , an exemplary embodiment of a high-efficiency lawnmaintenance tool 20 is shown. The high-efficiency lawn maintenance tool20 is shown as being a walk-behind mower, but it should be understood byone having ordinary skill in the art that the high-efficiency lawnmaintenance tool 20 may also be a riding mower, a stand-on mower, arobotic mower, a manual-powered mower, or any other tool configured tomow a lawn. FIG. 1 shows a traditional walk-behind mower with aninternal combustion engine. FIG. 2 shows a high-efficiency lawnmaintenance tool as a battery-powered electric walk-behind lawn mower.Of course, other examples are also possible, such as a corded electricwalk-behind model. The high-efficiency lawn maintenance tool 20 caninclude a frame 24. In one example, the frame 24 provides a skeletalsupport for many if not all of the remainder of the components that makeup the high-efficiency lawn maintenance tool 20. This feature eliminatesthe need for a typical “deep draw” deck of stamped metal that can oftenbe heavy and relatively expensive to manufacture due to strength anddurability requirements to support the remainder of the mower parts. Theframe 24 can comprise a metal structure or any other material suited forthe strength and durability requirements of the frame 24. In an example,the frame 24 can be constructed of tubular metal components arranged ina “U”-shape and oriented such that the open portion of the U is facingthe forward direction (represented by arrow 26) of the high-efficiencylawn maintenance tool 20.

The high-efficiency lawn maintenance tool 20 includes ground engagingmembers 28 attached to the frame 24. Any suitable ground engaging member28 can be used with the described high-efficiency lawn maintenance tool20 including, but not limited to, pneumatic tires, non-pneumatictires/wheels, track assemblies, and wheels with built-in suspensionfeatures. The ground engaging members 28 can be wheels attached to theframe 24 with a snap-on feature that does not require tools, such ashand tools.

The high-efficiency lawn maintenance tool 20 includes a deck 30. Thedeck 30 can include various parts including a deck shell 32. Use of thebelow described high-efficiency blade assembly enables the deck shell 32and the deck 30 to be of relatively short vertical height when comparedto many known walk-behind mower decks. This lessened height requirement,or “low profile” deck, can provide benefits such as minimized storagevolume requirements, minimized shipping volume requirements and thelike. The deck shell 32 can be constructed of any suitable material, forexample, molded plastic.

The high-efficiency lawn maintenance tool 20 includes a power source 36(best seen in FIG. 23 ) configured to provide rotational power to ahigh-efficiency blade used to cut grass and/or vegetation. In theillustrated embodiment of FIG. 2 , the power source 36 is abattery-powered electric motor, but it should be understood by onehaving ordinary skill in the art that the power source 36 may also be aninternal combustion engine, a hybrid-electric motor, or any other powersource capable of providing a rotational power output. The power source36 is mounted to one or both of the frame 24 and the deck 30, and thepower source 36 includes a drive shaft (not shown) extending through theframe 24 and the deck 30.

The illustrated exemplary embodiment of high-efficiency lawn maintenancetool 20 includes a user-operated handle 40 connected to the frame 24and/or the deck 30. In one example, the collapsible handle is“U”-shaped, with the ends of the U being mounted to the handle mountsand the closed portion of the U serving as a handle for an operator topush or otherwise control the high-efficiency lawn maintenance tool 20.The collapsible handle can include any number of ergonomic designs toease operator interaction. In another example, the handle 40 cancomprise a “J”-shape that connects to the frame 24 on only one side. Ofcourse, other shapes of handle 40 are also contemplated.

The handle 40 can be folded toward the frame 24 for storage and/orshipping purposes. The handle 40 can include a simple electrical circuit(not shown) to prevent operation of the power source 36 when the handle40 is in a folded position and is not in a suitable position foroperation of the high-efficiency lawn maintenance tool 20. For example,the electrical circuit can include a switch that breaks the electricalconnection between the power source 36 and a set of batteries 44 (bestseen in FIG. 23 ). When the electrical connection is broken, thehigh-efficiency lawn maintenance tool 20 cannot be operated. As such,the switch can be configured to complete the circuit (i.e., enable moweroperation) when the handle 40 is in one position or a number ofpositions that are suitable for mower operation. However, if the handle40 is outside of the selected position(s), the broken electricalconnection will prohibit mower operation, such as when the handle 40 isin the folded position for storage or shipping.

Turning to FIG. 3 , an exemplary embodiment of a high-efficiency blade46 includes a mounting portion 48 centered about a central axis 50. Thehigh-efficiency blade 46 also includes six arms with three lowerelevation arms and three higher elevation arms. In this disclosure, theterms higher elevation and lower elevation are terms used to comparedistances of the arms from a driven surface, (e.g., the ground or turf).For convenience, the disclosure will use the term “cleaning blade” 54for each higher elevation arm and the term “cutting blade” 56 for eachlower elevation arm.

Each cleaning blade 54 can include three bends 58, 60, 64 which will bedescribed from the center of the high-efficiency blade 46 radiallyoutward. The first bend 58 is adjacent the mounting portion 48 of thehigh-efficiency blade 46 and the first segment 66 following the firstbend 58 extends toward the underside of the deck 30. The second bend 60leads to the second segment 68 angled slightly downward, where thisdownward direction maintains the second segment 68 generally parallel tothe underside of the deck 30. The third bend 64 is near a tip portion 70of the cleaning blade 54 after which a third segment 74 extendsgenerally downward. This third bend 64 and third segment 74 are optionalfor the high-efficiency blade 46 shown in FIG. 3 , and can be omittedwithout significantly affecting the performance of the high-efficiencyblade 46. The described geometry of the cleaning blade 54 is but oneexample, and regardless of the shape and proportions of the cleaningblade 54, it is to be separated a distance from the cutting blade 56 andbe positioned at a particular distance from an underside of the mowerdeck 30 as will be described below.

The example high-efficiency blade 46 of FIG. 3 also shows three cuttingblades 56, each cutting blade 56 including two bends 76, 78 and twosegments 80, 84 which will be described from the center of thehigh-efficiency blade 46 radially outward. A first bend 76 leads to afirst segment 80 that is angled downward toward the driven surface. Asecond bend 78 leads to a generally horizontal second segment 84, andthe elevation of the second segment 84 corresponds to a desired cutheight of the grass/vegetation that is to be cut by the high-efficiencylawn maintenance tool 20. As shown, the cleaning blade 54 and thecutting blade 56 elevations can alternate going around thehigh-efficiency blade 46, with each cutting blade 56 located between twocleaning blades 54 and each cleaning blade 54 located between twocutting blades 56. However, any suitable number of cleaning blades 54and cutting blades 56 can be used on the high-efficiency blade 46provided that the high-efficiency blade 46 is rotationally balanced.

The cutting blade 56 includes cutting blade sharpened leading edges 86configured to cut grass and/or vegetation as the high-efficiency blade46 is rotated. As shown in FIG. 4 , the cutting blades 56 includecutting blade sharpened leading edges 86 that are located on the secondsegments 84, again, at an elevation 88 that corresponds to a desired cutheight of the grass/vegetation to be cut. It is to be understood thatthe point 90 of the cutting blade sharpened leading edge 86 is on thelower surface 94 of the second segment 84 to help provide a clean cut ofthe grass/vegetation. In at least one example, the cutting bladesharpened leading edge 86 is generally parallel to the driven surface.Generally parallel can be within one or two degrees from a horizontal.

Similar to an airfoil, the angled side 96 of the cutting blade sharpenedleading edge 86 provides a longer path (represented by arrow 98) for airpassing above the second segment 84 than the shorter path (representedby arrow 100) for air passing underneath the second segment 84 as thehigh-efficiency blade 46 rotates. This creates a lower air pressure zoneabove the second segment 84 as it rotates through the air in a directionaccording to arrow 104 and helps extend the grass and/or vegetation forcutting, in addition to helping propel the clippings to the cleaningblades 54.

Turning to FIG. 5 , one example of the cleaning blades 54 can alsoinclude cleaning blade sharpened leading edges 106. On the cleaningblade second segments 68, the cleaning blade sharpened leading edge 106can be formed at a reverse angle when compared to the cutting bladesharpened leading edge 86, such that a point 108 of the cleaning bladesharpened leading edge 106 is on an upper surface 110 of the secondsegment 68. Similar to the cutting blade sharpened leading edge 86, thecleaning blade sharpened leading edge 106 provides a longer path(represented by arrow 114) for air passing underneath the second segment68 than the shorter path (represented by arrow 116) for air passingabove the second segment 68 as the high-efficiency blade 46 rotates.This creates a lower air pressure zone underneath the second segment 68as it rotates through the air in a direction according to arrow 118 andhelps keep the underside of the deck 30 clean, as will be discussedbelow. Furthermore, the air pressure difference can help move the grassclippings cut again by the cleaning blade second segment 68 to be moveddownward, away from the underside of the deck 30.

Turning to FIG. 6 , another example of a high-efficiency blade 119 isshown. High-efficiency blade 119 is similar to the high-efficiency blade46 of FIG. 3 , but only includes two segments (first segment 66 andsecond segment 68) on each cleaning blade 54. In other words, eachcleaning blade 54 does not include bend 64 or segment 74. Instead, eachcleaning blade 54 terminates at the outer edge of the second segment 68.Elimination of the third segment that extended generally downward can,in some circumstances, reduce the amount of airflow while alsoeliminating a surface that can undesirably collect grass and/orvegetation clippings.

Turning to FIG. 7A, another example of a high-efficiency blade 120 isshown from a bottom side 124. The high-efficiency blade 120 includes amounting plate 126, a plurality of cleaning blades 128, a plurality ofcutting blades 130, and a plurality of quick-attach mechanisms 134 thatallow the cutting blades 130 to be easily attached to and detached fromthe mounting plate 126. The high-efficiency blade 120 is configured tobe easily removed and attached as desired to the high-efficiency lawnmaintenance tool 20, and the cutting blades 130 are similarly easilyremoved and attached as desired to the high-efficiency blade 120.

The cleaning blades 128, when rotating, form a physical barrier betweenthe cutting blades 130 and the deck 30 as well as between the cut grassand the deck 30, as shown in FIGS. 7A and 7B. The mounting plate 126 isconfigured to be rotatably driven by a drive shaft 294 (one example isshown in FIG. 8 ) extending from the power source 36. As described abovewith other versions of the high-efficiency blade, the cleaning blades128 are also configured to direct cut grass downwardly toward theground. The cleaning blades 128 are generally formed such that whenrotating, form a volume of revolution as an inverted bowl shape having asomewhat W-shaped configuration, when viewed in the cross-section. Wheninstalled on the high-efficiency lawn maintenance tool 20, the open sideof the bowl-shaped volume of revolution created by the cleaning blades128 is directed downwardly toward the ground. The drive shaft 294 thatextends downwardly from the power source 36 extends through a centralaperture 136 of the mounting plate 126. In the illustrated exemplaryembodiment, the mounting plate 126 includes four (4) slots 138 that areequally spaced about the central aperture 136. The slots 138 areoriented in a tangential manner relative to a radial edge 140 of themounting plate 126, and the slots 138 are positioned about ninetydegrees (90°) relative to each other relative to the central aperture136. The slots 138 are configured to receive a portion of the biasingmember of the quick-attach mechanism 134, as explained below.

As shown in FIGS. 7A and 7B, the mounting plate 126 includes a pluralityof quick-attach mechanisms 134 that allow for an easy and fast mannerfor attaching and detaching the cutting blades 130 from the mountingplate 126. The quick-attach mechanisms 134 work in conjunction with aconnecting aperture as well as the size and shape of the cutting blades130 to provide for a tool-less connection between the cutting blades 130and the mounting plate 126, wherein a tool such as a wrench,screwdriver, or any other handheld tool is not necessary to attach ordisconnect the cutting blades 130. In an embodiment, each quick-attachmechanism 134 includes a biasing member 144 operatively connected to themounting plate 126. The biasing member 144 is configured to bias thecutting blades 130 into being positively attached to the mounting plate126 when properly attached thereto or, alternatively, to bias thecutting blades 130 away from the mounting plate 126 such that thecutting blades 130 cannot be attached to the mounting plate 126 if thecutting blades 130 are not properly aligned or are not properlyconnected.

The biasing member 144 is configured as a generally L-shaped spring, asshown in FIG. 7A. In an embodiment, the biasing member 144 is metal, butit should be understood by one having ordinary skill in the art that thebiasing member 144 may also be formed of plastic or other flexiblematerial that allows the biasing member 144 to act as a spring. Thebiasing member 144 includes a base 146, a body 148 extending from thebase 146, a curved portion 150, and a bearing portion 154. The base 146of the biasing member 144 is configured as a substantially flatcomponent and is configured to receive an attachment mechanism 156 forconnecting the biasing member 144 to the mounting plate 126. Theattachment mechanism 156 can be a nut-and-bolt, rivet, or similarmechanical fastener sufficient to connect the biasing member 144 to themounting plate 126.

The biasing member 144 is attached to the mounting plate 126 in acantilevered manner, wherein the distal end of the biasing member144—defined by the base 146—is attached to the mounting plate 126 andthe remainder of the biasing member 144 extends therefrom. Theillustrated embodiment shows the base 146 as having two (2) attachmentmechanisms 156 for attachment to the mounting plate 126, but it shouldbe understood by one having ordinary skill in the art that the mountingplate 126 may include any number of attachment mechanisms 156. The base146 is attached to the surface of the mounting plate 126 and extendsthrough a corresponding opening of the mounting plate 126 such that thebody 148, curved portion 150, and bearing portion 154 are generallypositioned below a downward facing lower surface of the mounting plate126.

The body 148 of the biasing member 144 of each quick-attach mechanism134 extends from the base 146 at an angle, as shown in FIG. 7A. The body148 is a generally flat component that is integrally connected with thebase 146. It is the angle formed between the base 146 and the body 148that provides the spring action when the biasing member 144 is actuated.The body 148 extends downwardly (directionally, when the high-efficiencyblade 120 is attached to the lawn maintenance tool 20) below thedownward facing lower surface of the mounting plate 126. One distal endof the body 148 is integrally formed with the base 146, and the opposingdistal end of the body 148 is integrally formed with the curved portion150. The curved portion 150 extends from the body 148 in a curvedmanner, wherein the curved portion 150 is curved upwardly toward thedownward facing lower surface 158 of the mounting plate 126. The curvedportion 150 connects the body 148 and the bearing portion 154, whereinthe bearing portion 154 extends from the curved portion 150 at an anglerelative to the body 148. While the body 148 of the biasing member 144extends away from the downward facing lower surface 86 of the mountingplate 126, the bearing portion 154 extends toward (and beyond) the lowersurface 158 of the mounting plate 126. The bearing portion 154 isconfigured to move into and out of the corresponding slot 138 duringactuation of the biasing member 144, as will be explained below. Whenactuated, the biasing member 144 rotates about the transition betweenthe body 148 and the base 146 such that the bearing portion 154 movestoward the mounting plate 126. The bearing portion 154 includes abearing surface 160 that is configured to contact the cutting blade 130and bias the spring either into engagement when properly aligned duringattachment or into disengagement when not properly aligned duringattachment.

In an embodiment, a cap 164 of the quick-attach mechanism 134 extendsdownwardly from the downward facing lower surface of the mounting plate126, as shown in FIG. 7A. Each cap 164 includes a post 166 and a plate168, wherein the post 166 is attached to the mounting plate 126 and theplate 168 is attached to the opposing distal end of the post 166. Thepost 166 is a generally cylindrical member that is integrally formedwith the mounting plate 126. In an embodiment, the post 166 is attachedto the mounting plate 126 by way of a weld or other means forpermanently attaching the post 166 to the mounting plate 126. The plate168 is oriented generally parallel to downward facing lower surface ofthe mounting plate 126. The plate 168 can be a generally oval-shapedmember. Each cap 164 is configured to allow a cutting blade 130 to bereleasably attachable thereto. The plate 168 is spaced apart from themounting plate 126 a distance that is substantially the same as thethickness of the cutting blade 130—or just slightly larger—to reduce oreliminate shaking movement of the cutting blade 130 relative to themounting plate 126. The plate 168 is sized and shaped to be received bythe cutting blade 130.

As shown in FIGS. 7A and 7B, an exemplary embodiment of a cutting blade130 is a generally elongated Z-shaped blade having a mounting portion170, a transition portion 174, and a tip portion 176. The mountingportion 170 is formed as a flat portion having an aperture 178 formedtherethrough. The aperture 178 is formed as an elongated oval shape,wherein the aperture 178 is shaped to correspond to the shape of theplate 168 of the cap 164. The transition portion 174 extends from themounting portion 170 at an angle therefrom, wherein the transitionportion 174 extends away from the downward facing lower surface of themounting plate 126. The tip portion 176 extends from the transitionportion 174 at an angle thereto, wherein the tip portion 176 and themounting portion 170 are substantially parallel relative to each other.The cutting blade 130 includes a sharpened leading edge 180 xx configureto cut grass as the high-efficiency blade 120 is rotated. When thecutting blades 130 are properly installed on the high-efficiency blade120, the distal end of the tip portion 176 is positioned adjacent to theradial edge 140 of the revolution of volume formed by the rotatingcleaning blades 128. In an embodiment, the distal end of the tip portion176 is positioned radially inward relative to the radial edge 140 of therevolution of volume formed by the rotating cleaning blades 128.

In operation, the cutting blades 130 are operatively connected to thehigh-efficiency blade 120 by way of the quick-attach mechanism 134. Thecutting blade 130 is first positioned adjacent to the cap 164 of thequick-attach mechanism 134 such that the aperture 178 of the cuttingblade is aligned with the cap 164. The cutting blade 130 is then pushedtoward the mounting plate 126, wherein the cap 164 of the quick-attachmechanism 134 is received in the aperture 178 of the cutting blade 130.Further, the mounting portion 170 of the cutting blade 130 contacts thebody 148 and curved portion 150 of the biasing member 144, and as thecutting blade 130 is moved toward the mounting plate 126, the biasingmember 144 is actuated by bending and rotating in a cantilevered manner.If the cutting blade 130 is not fully attached to the cap 164, thebiasing member 144 biases the cutting blade 130 away from the mountingplate 126 such that the cutting blade 130 is disengaged from the cap164. As the biasing member 144 is actuated, the bearing portion 154extends through the corresponding slot 138 of the mounting plate 126.Once the cutting blade 130 has been pushed until it is flush with themounting plate 126, the cutting blade 130 is then pulled radially towardthe radial edge 140 of the mounting plate 126 until the post 166 of thecap 164 contacts the end of the elongated aperture 178 formed throughthe cutting blade 130. As the cutting blade 130 slides radially outward,the mounting portion 170 of the cutting blade 130 slides along the body148 and curved portion 150 of the biasing member 144 after which thedistal end of the cutting blade 130 slides along the bearing surface(downward facing surface) of the bearing portion 154. In this position,the cutting blade 130 is positively attached to the quick-attachmechanism 134 extending from the mounting plate 126, and the spring biasgenerated at the curved portion 150 of the biasing member 144continually pushes radially against the edge at distal end of thecutting blade 130. This radial bias from the biasing surface against thecutting blade 130 ensures continuous attachment between the cuttingblade 130 and the mounting plate 126. This radial bias also preventsaccidental disconnection of the cutting blade 130 by preventing thecutting blade 130 from sliding radially toward the central aperture 136of the mounting plate 126. The mounting portion 170 of the cutting blade130 is sandwiched between a portion of the cap 164 and the mountingplate 126 to reduce or eliminate any “bounce” at the distal end of thetip portion 176.

The cutting blade 130 is removed by actuating—or pressing—the biasingmember 144 toward the mounting plate 126, thereby removing the radialbearing force applied to the cutting blade 130 and effectivelydisengaging the cutting blade 130 from the biasing member 144. Thecutting blade 130 is then slid radially inward toward the centralaperture 136 of the mounting plate 126 until the entire plate 168 of thecap 164 is aligned with the aperture 178 of the cutting blade 130. Atthis point, the cutting blade 130 can be removed from the quick-attachmechanism 134.

As noted previously, the quick-attach mechanism 134 allows the cuttingblades 130 to be releasably attachable to the mounting plate 126 withoutthe use of any handheld tools or other tool separate from thehigh-efficiency blade 120.

Turning to FIG. 7B, the high-efficiency blade 120 is shown from a topside 179. The high-efficiency blade 120 includes a mounting plate 126, aplurality of cleaning blades 128, a plurality of cutting blades 130, anda plurality of quick-attach mechanisms 134 that allow the cutting blades130 to be easily attached to and detached from the mounting plate 126.The high-efficiency blade 120 can be configured to be easily removed andattached as desired to the high-efficiency lawn maintenance tool 20, andthe cutting blades 130 are similarly easily removed and attached asdesired to the high-efficiency blade 120.

Turning to FIG. 8 , regardless of the number of bends 58, 60, 64 orsegments 66, 68, 74 in any of the example cleaning blade 54, 128, atleast one segment of the cleaning blade 54, 128 is generally parallel tothe underside of the deck 30. This same segment is maintained at arelatively close distance from the underside of the deck 30 asrepresented by dimension 180 in FIG. 8 . In the shown example, thesecond segment 68 is located about one-inch to 1/16-inch from theunderside of the deck 30. In a more particular example, the secondsegment 68 is located about ½-inch to 1/16-inch from the underside ofthe deck 30. In yet a more particular example, the second segment 68 islocated about ¼-inch to 1/16-inch from the underside of the deck 30. Thedimension 180 can be optimized to encourage optimal mulching of thegrass clippings and improved cleanliness of the underside of the deck30. One factor in the optimization process can be the rotational speedof the high-efficiency blade 46, 120. In one example, as the rotationalspeed of the high-efficiency blade 46, 120 is reduced, the optimizeddimension 180 is also reduced.

Another goal of the cleaning blades 54 is to reduce and/or eliminatebuildup of grass clippings on the underside of the deck 30. Thiscleaning function can be accomplished in at least three ways by thecleaning blades 54. First, the cleaning blades 54 can knock the grassclippings downward toward the turf/driven surface as the cleaning blade54 strikes the grass clipping after it is propelled upward by thecutting blade 56 during the cutting function. This action of knockingdown the grass clippings can prevent the grass clippings contacting theunderside of the deck 30 and then sticking to the underside of the deck30. Second, the cleaning blades 54 can direct the grass clippings and anairflow in a direction radially away from the central axis 50. Thisoutward flow can also help reduce and/or eliminate attachment of grassclippings to the underside of the deck 30. Third, the close proximity ofthe cleaning blade segment 68 to the underside of the deck 30 can affectthe air pressure in the boundary layer of air adjacent the underside ofthe deck 30. For example, as the cleaning blade segment 68 close to theunderside of the deck 30 approaches a particular point on the undersideof the deck 30, the segment 68 is pushing a wave of air. This causes anincrease in the air pressure about the particular point. As the segment68 passes, the air pressure is reduced, thereby creating a sinusoidaleffect in the air pressure about any given point on the underside of thedeck 30. This variable pressure wave, or periodic pressure increase anddecrease, which has a relatively high frequency due to the rotationalspeed of the high-efficiency blade 46, reduces the likelihood of grassclippings becoming attached to or stuck to the underside of the deck 30.

As a brief summary, each of these functions enables the cleaning blades54 to replicate the effects of a solid disk rotating in unison with thecutting blades 56. After grass blades or other vegetation are cut by thecutting blades 56, the clippings are typically propelled in the air fora time, during which time the cleaning blades 54 strike and cut thegrass clippings one or more times. Impact with the cleaning blades 54tends to urge the grass clippings radially outward from the central axis50 and downward toward the turf. The periodic pressure change in thevolume of air adjacent the underside of the deck 30 further aids inreducing and/or eliminating grass clipping build-up on the underside ofthe deck 30. In this way, the high-efficiency blade enables thehigh-efficiency lawn maintenance tool 20 to become a self-cleaningdevice.

Turning to FIG. 9 , another example of a high-efficiency blade 184 isshown, and it is to be appreciated that any number of structuresincluding cleaning blades with sharpened edges and cutting blades havingsharpened edges are contemplated. The version of the high-efficiencyblade 184 shown in FIG. 9 includes three arm sections 186 with each armsection including a cleaning blade 188 and a cutting blade 190. Thehigh-efficiency blade 184 of FIG. 9 can include a mounting portion 194providing a mounting location for each of the three arm sections 186.Each of the three arm sections 186 can be mounted to the mountingportion 194 by any suitable structure or method. Similar to thehigh-efficiency blade 46 of FIG. 3 , the high-efficiency blade 184 ofFIG. 9 includes cutting blades 190 configured to cut grass and/or othervegetation while the cleaning blades 188 are configured to mulch theclippings and keep the underside of the deck 30 relatively free and/orcompletely free of an accumulation of clippings.

Turning to FIG. 10 , an exploded view of a mounting assembly 196 foranother example high-efficiency blade 198 is shown. While any suitablemounting structure for the high-efficiency blade 198 is acceptable, themounting assembly 196 shown in FIG. 10 provides one example. Themounting assembly 196 mounts to the spindle or motor shaft (not shown)of the power source 36 (e.g., electric motor, internal combustionengine, etc.) to mount the high-efficiency blade 198 to the spindle orshaft while eliminating relative motion between the high-efficiencyblade 198 and the spindle or shaft. FIG. 11 shows an assembled view ofthe components of FIG. 10 , and FIGS. 12 and 13 show detail views of twoof the mounting assembly 196 components. FIGS. 11-13 may assist theunderstanding of the mounting assembly if these additional figures arereferenced together with FIG. 10 .

The high-efficiency blade 198 configuration of FIG. 10 includes eightarms 200; four cleaning blades 204 and four cutting blades 206 emanatingfrom a central mounting portion 208. Like the previously describedhigh-efficiency blades 46, 120 the arm type alternates around theexterior of the central mounting portion 208. In other words, eachcleaning blade 204 is located between two cutting blades 206, and eachcutting blade 206 is located between two cleaning blades 204. Themounting portion 208 defines a central aperture 210 and a plurality ofdrive apertures 214 located on a circle having a greater diameter thanthe central aperture 210.

An example mower deck 30 is shown at the top of FIG. 10 . Directlyunderneath the deck 30, a motor mount 216 is shown that includes a stemportion 218 and a flat, disk portion 220. As shown in FIG. 12 , themotor mount 216 defines a central through-hole 224 configured tocooperate with a portion of the spindle or shaft. In one example, thethrough-hole 224 includes a non-circular cross-sectional profile 226which can include, but is not limited to a “Double-D” shape. Thethrough-hole 224 is configured to cooperate with a similar, reverseshape on the spindle or shaft and fit snugly to the spindle or shaft.FIG. 12 shows the motor mount 216 upside-down from its normalorientation in the mounting assembly 196 in order to better showparticular features. The disk portion 220 of the motor mount 214 has agreater diameter 228 than a diameter 230 of the stem portion 218. Thedisk portion 220 also includes a stepped area 234 that is notable for anon-circular shape 236, such as a Double-D shape.

Returning to FIG. 10 , a leaf spring 238 is located directly below themotor mount 216. The leaf spring 238 detail is shown in FIG. 13 , and isalso shown upside down relative to its normal orientation in themounting assembly 196. The leaf spring 238 defines a central aperture240 having a non-circular shape, such as a Double D shape to eliminaterelative movement between the leaf spring 238 and the motor mount 216.The leaf spring 238 includes a plurality of drive knobs 244 located on adownward-facing side 246, or the side adjacent the high-efficiency blade198. It is to be understood that the circular portion 248 of the steppedarea 234 Double D of the motor mount 216 can pilot the central aperture210 of the high-efficiency blade 198 while the flat portions 250 of theDouble D arrangement can pilot the central aperture 240 of the leafspring 238. The drive knobs 244 are located on a circle of the samediameter as the drive apertures 214 on the high-efficiency blade 198 ofFIG. 10 . The drive knobs 244 are configured to cooperate with the driveapertures 214 to pass rotational power from the spindle or shaft, themotor mount 216, and the leaf spring 238 to the high-efficiency blade198.

As shown in FIG. 10 , a washer 254 is located beneath thehigh-efficiency blade 198, and a fastener (e.g., a threaded fastener)(not shown) is used to secure the mounting assembly 196 to the spindleor shaft. As shown in FIG. 11 , the leaf spring 238 and thehigh-efficiency blade 198 are sandwiched between the motor mount 216 andthe washer 254. The mounting assembly 196 can be maintained in thisposition by a screw (not shown) that threads into a female threadedportion of the spindle or shaft. The female threaded portion is coaxialwith the spindle or shaft.

The disk portion 220 of the motor mount 216 and the washer 254 form agap (shown by dimension 256) in the mounting assembly 196 that can be abit longer than the sum of the heights of the high-efficiency blade 198and the leaf spring 238. This extra distance helps ensure that therotational force for the high-efficiency blade 198 is provided at thedrive knobs 244 and drive apertures 214 rather than relying on aclamping force between the washer 254 and the motor mount 216. Thisarrangement is intended to enable the high-efficiency blade 198 torotate to cut grass and vegetation, but when striking a firm object(e.g., a pipe or a rock), the high-efficiency blade 198 may slip free ofthe rotation restraint provided by the leaf spring 238. This freerotation condition is intended to prevent significant twisting and orbending moments that may damage the high-efficiency blade 198 and thedeck 30.

As can be seen in FIG. 11 , the stem portion 218 of the motor mount 216can also define a shoulder 258 in the through-hole 224. This shoulder258 can cooperate with a shoulder (not shown) on the spindle or shaft topositively locate the mounting assembly 196.

There are several aspects of the example high-efficiency blades and thehigh-efficiency lawn maintenance tool 20 that render them to be“high-efficiency.” First, many known mower blades include a “ramp” or“sail” located at the trailing edge of a rotating blade. The sail isplaced on the blade to generate considerable airflow beneath thestandard mower deck. This airflow can be effective to: a) pull blades ofgrass upward in order to be cut by the rotating blade and b) move grassclippings toward and through a chute opening defined by the deck.Approximately 50% of all the power required to drive a conventionalcutting system is used to generate this airflow.

However, the described cutting system provides a 50% reduction inairflow as actually measured when compared to standard internalcombustion engine mowers with a standard rotating cutting blade having asail. The same 50% reduction in airflow is measured when the device ofthe present disclosure is compared to electrically-operated mowersemploying a typical cutting blade.

Additionally, it is worthy of note that for moving objects (e.g., arotating mower blade), measured air resistance is a square function ofthe velocity of the rotating object. In the disclosed high-efficiencyblade, there are four (4) grass cutting edges compared to two (2)cutting edges on a standard mower blade. With at least double the numberof cutting blades, the described cutting devices can operate at areduced revolutions per minute (rpm) when compared to typical mowerblades. Thus, the reduction in rpm operation reduces the powerrequirement of the blade. For example, an rpm reduction by half wouldresult in ¼ of resultant air resistance due to the square functionrelationship between velocity and air resistance.

As such, the high-efficiency blades described in this disclosure bothreduce the total requirement for airflow generation and reduce theoverall air resistance as the high-efficiency blade rotates through theair, the blade is significantly more efficient that a typical mowerblade. This greater efficiency results in a reduced power requirementfrom a power source leading to increased run times for battery-operatedmowers, increased fuel efficiency for internal combustionengine-operated mowers, or decreased demand for electrical draw from acorded, electrically-operated mower. For example, if the powerconsumption of the described devices are half of the power consumptionof typical mowers, then the run time of the battery-operated mower istwice that of the typical battery-operated mower. In other words, a 50%increase in efficiency for a battery-operated mower results in 50%longer run time on the same battery or battery system.

The remainder of the disclosure will refer to only one high-efficiencyblade 46, however, it is understood that several versions of ahigh-efficiency blade can be used in the described high-efficiency lawnmaintenance tool 20.

In some examples of lawn maintenance tools including a high-efficiencyblade 46, it may be advantageous to alter the separation distancebetween the cleaning blade 54 of the high-efficiency blade 46 and theunderside of the deck 30 as represented by dimension 180 in FIG. 8 .Turning to FIG. 14 , a top view of an example deck 30 is shown includingthree shaded areas 260, 264, 266. Each of the shaded areas 260, 264, 266includes a separation distance between the cleaning blade 54 and theunderside of the deck 30 that is different from the separation distance180 provided in the non-shaded portions of the deck 30. As thehigh-efficiency blade (not shown) turns in a direction represented byarrow 268, a significant accumulation of grass clippings may collect andbe forced down into the turf grass in a particular linear arrangement,leaving a path of bent-over grass represented by area 270.

The cross-section view of FIG. 15 shows the standard separation distance180, which is the same as that shown in FIG. 8 . FIG. 16 shows anincreased separation distance 274 in one portion of the deck 30. Inother words, the separation distance 274 is increased in this area 260due to a deeper draw on that portion of the deck 30. The deck height inthis area 260 can be constant and generally parallel to the drivensurface (e.g., the turf), however, any suitable arrangement isacceptable. The cross-section view of FIG. 17 represents an area 264 ofincreasing separation distance 276, and serves as a transition area 264from the part of the deck 30 having a typical separation distance 180 tothe part of the deck 30 having the increased separation distance 274shown in FIG. 16 . The transition surface 278 may be of any suitablearrangement, such as ones having a linear profile similar to a ramp, orcurvilinear, etc.

The cross-section view of FIG. 18 shows another transition area 266 inwhich the separation distance 280 decreases from the separation distance274 of FIG. 16 to the typical separation distance 180 of the remainderof the deck 30 shown in FIG. 15 . The cross-section of FIG. 18 can beidentical to the cross-section of FIG. 17 , save that the separationdistance 280 is increasing as the cleaning blade 54 rotates in theclockwise direction in FIG. 17 , and decreasing as the cleaning blade 54rotates in the clockwise direction in FIG. 18 . Again, any suitableprofile for the deck transition height is acceptable, including ramps,curvilinear surfaces, etc.

Returning to FIG. 14 , these areas 260, 264, 266 of the deck 30 having agreater separation distance can accommodate relatively largeaccumulations of grass clippings while reducing and/or eliminatingpatterns of bent-over grass arising from the relatively largeaccumulations. There are a number of factors that can alleviate thebent-over grass condition, including a larger volume of space for thegrass clippings to occupy, thereby some clippings require a longer pathand longer time period to return to the turf below, spreading thedistribution of mulched grass over a wider area. Additionally, thecleaning blade 54 of the high-efficiency blade 46 can strike the grassclippings a number of additional times, thereby creating smallerclippings that will have a decreased tendency to bend the uncut grass.

To this point, the disclosure has primarily discussed single-spindlelawn maintenance tools, such as those shown in FIGS. 1 and 2 . It is tobe understood that the design of the high-efficiency lawn maintenancetool 20 can be scalable to larger or smaller needs. For example, alarger walk-behind mower or a riding mower may require a larger singlehigh-efficiency blade. Alternatively, the high-efficiency lawnmaintenance tool 20 can also include a plurality of high-efficiencyblades 46 of any scalable size. For example, FIG. 19 shows an explodedview of an example mounting assembly 284 for a plurality ofhigh-efficiency blades 46 for a multi-spindle high-efficiency lawnmaintenance tool 20, more specifically, a five-spindle high-efficiencylawn maintenance tool.

The mounting assembly 284 of the high-efficiency blade 46 for amulti-spindle high-efficiency lawn maintenance tool 46 can include abelt cover 286 that cooperates with a deck 30 to enclose severalhigh-efficiency blade drive components of the mounting assembly 284within an interior space 288. The belt cover 286 can be attached to thedeck 30 in any number of suitable arrangements and fasteners are notshown in FIG. 19 . The belt cover 286 defines one aperture 290coinciding with a drive spindle 294 and five apertures 296 coincidingone each to the five driven spindles 298. The apertures 290, 296 areconfigured to enable passage of a portion of each spindle 294, 298through the belt cover 286 where a threaded fastener 300 can help ensureproper mounting and location of the spindles 294, 298. In one example,the belt cover 286 and the deck 30 can be configured to mate such thataccumulations of dirt and other unwanted particles are minimized and/oreliminated from the interior space 288. In some examples, there may be abelt cover bottom 304 (best seen in FIG. 8 ) between the deck 30 and thedrive components that is configured to interact with the belt cover 286to help seal the interior space 288 for the drive components.

Moving from the top down, each spindle 294, 298 includes theaforementioned threaded fastener 300 (e.g., a threaded nut) at the topthat can cooperate with a threaded end 306 of the spindle 294, 298. Eachspindle 294, 298 passes through a cover bearing 308 to provide asuitable axis of rotation 310 for the spindle 294, 298. The coverbearings 308 can be captured by the belt cover 286 as shown in in thecross-section view of FIG. 8 . Returning to FIG. 19 , the drive spindle294 passes through a drive pulley 314 or gear. Similarly, the drivenspindle 298 passes through a driven pulley 316. The spindle 294, 298 maybe molded into the pulley 314, 316, press-fit into the pulley 314, 316or attached in any other suitable manner. The pulleys 314, 316 arecogged in order to provide a timing function with respect to each of theother pulleys 314, 316. The spindle 294, 298 then passes through a deckbearing 318 that is configured to be captured by the deck 30 as shown inFIG. 8 . Returning to FIG. 19 , after the driven spindles 298 passthrough the deck 30, a high-efficiency blade attachment member 320rotationally fixes the high-efficiency blade 46 to the driven spindle298. At a lower end 324 of the driven spindle 298, the high-efficiencyblade 46 is vertically fixed to the driven spindle 298 by a fastener 326(e.g., a threaded nut) that cooperates with the lower end 324 of thedriven spindle 298.

In the shown example, the drive spindle 294 can have minor variationsfrom the driven spindles 298. For example, the drive spindle 294 can belonger in order to provide a connection to a suitable rotational powersource. In another example, the drive spindle 294 can be the drive shaftof an electric motor or an internal combustion engine.

The drive components within the interior space 288 further include atleast one drive belt 328 configured to transfer rotational power fromthe drive spindle 294 to the driven spindles 298. In the shown example,there are two serpentine drive belts 328, 330 that are cogged on bothsides of the drive belt 328, 330. Belt teeth are not shown in FIG. 19 inorder to minimize the complexity of the drawing.

Turning to FIG. 20 , each of the drive pulley 314 and the driven pulleys316 include a suitable height dimension 334 such that both drive belts328, 330 can interact with any given pulley 314, 316 simultaneously,each drive belt 328, 330 interacting with the teeth of the pulley 314,316 at a separate elevation. This detail view of the drive spindle 294and the drive pulley 314 shows the simultaneous interaction of the twodrive belts 328, 330 with the single drive pulley 314.

Turning to FIG. 21 , the high-efficiency blade 46 drive components areshown in a top view with the belt cover 286 removed for clarity. A firstdrive belt 328 interacts with the drive pulley 314 to receive power thatis transmitted to the driven pulleys 316 as the first drive belt 328rotates about the pulleys 314, 316. Similarly, a second drive belt 330is located at a different elevation and takes rotational power from thedrive pulley 314 and transmits that rotational power to the drivenpulleys 316. In this top view, if the drive pulley 314 is rotated in theclockwise direction, each of the three center and left-side drivenpulleys 336 rotate in the counter-clockwise direction, and each of thetwo right-side driven pulleys 338 rotate in the clockwise direction. Asthe high-efficiency lawn maintenance tool 20 moves in the directionrepresented by arrow 340, the grass clippings cut by the high-efficiencyblades 46 associated with the driven pulleys 344 is urged in a directiontoward the outside of the high-efficiency lawn maintenance tool 20rather than toward the interior.

It is to be appreciated that several variables can be altered in orderto attain desired high-efficiency blade 46 direction of rotation,rotational speed, etc. to achieve conditions that will best cut grassand vegetation. For example, the path of the drive belts 328, 330 ischosen to achieve the described rotation pattern of the high-efficiencyblades 46. Other rotation patterns are also contemplated. In anotherexample, the ratio of the drive pulley 314 diameter to the driven pulley316 diameter and the number of teeth on each pulley 314, 316 can bemodified to obtain a desired high-efficiency blade 46 rotation speed.

Turning to FIG. 22 , a bottom view of the high-efficiency blades 46 inthe multi-spindle mounting assembly 284 is shown. Similar to FIG. 21 ,if the lawn maintenance tool 20 is traveling in the direction of arrow340, the previously described arrangement of the drive components (notshown) causes clockwise rotation (when viewed from below), representedby arrow 346, of the high-efficiency blades 46 to the left and at thecenter of the figure. Counter-clockwise rotation, represented by arrow348, is created on the right side high-efficiency blades 46.

FIG. 22 also shows the multi-spindle arrangement can include a cuttingpath overlap 350 such that two high-efficiency blades 46 pass over aportion of grass to be cut. This helps reduce and/or eliminate thechance of uncut grass remaining after the high-efficiency lawnmaintenance tool 20 passes over a section of grass and/or vegetation.

When scaling the design for larger or smaller blade systems, amathematical relationship between the optimal number of cutting blades,cleaning blades, and the diameter of the high-efficiency blade can bedesigned for increased efficiency. The mathematical relationship caninclude a minimum of ten (10) blade passes per foot at a minimum. Thisrelationship may also place a maximum 19,000 feet per minute (fpm)high-efficiency blade 46 tip speed. In one example, a desiredhigh-efficiency blade 46 tip speed can be about 10,000 fpm. In anotherexample, the high-efficiency blade 46 can operate at about 2,200 rpmwith a projected 12,000 feet per minute (fpm) blade tip speed. This is asignificant reduction from a standard 21-inch diameter system that mayoperate at 3,200 rpm and have a 19,000 fpm blade tip speed.

It is to be understood that the deck 30 shown in FIGS. 8 and 19, 21, and22 can be made from any suitable material including, but not limited to,plastic. Furthermore, the deck 30 is configured to be in relativelyclose proximity to the cleaning blades 54 of the high-efficiency blade46 such that the underside of the deck 30 stays grass-free or relativelygrass-free. It may also be beneficial to include the feature includingincreased separation distance 274, 276, 280 between the cleaning blade54 of the high-efficiency blade 46 and the underside of the deck 30 asshown in FIGS. 14-18 in the multi-spindle deck configuration of FIG. 19.

It is also to be understood that the shown example of the multi-spindlelawn maintenance tool includes a single drive spindle 294 providingrotational power for five driven spindles 298. As previously described,the drive spindle 294 takes rotational power from a single power source36. In other examples, the serpentine drive belts 328, 330, drivespindle 294, and drive pulley 314 can be omitted for an arrangementhaving one power source (e.g., an electric motor) dedicated to eachdriven spindle 298. This one-to-one ratio of power sources to drivenspindles 298 and, therefore, high-efficiency blades 46 can give rise tousing larger numbers of smaller power sources which can lower the costof each power source to offset the increased number of power sources. Inother words, the power sources can be increased in number while findinga common power source size and rating that is commoditized, therebyenabling a cost benefit.

In the shown examples, the deck 30 does not include a chute for grassclippings, such that there is no exit port from which cut grassclippings are expelled from the lower volume, which is defined by thelower surface of the deck 30. The high-efficiency blade 46 of thehigh-efficiency lawn maintenance tool 20 is configured to cut the grassand the grass cuttings are then directed downwardly back toward theground, as explained above. As such, there are little to no quantitiesof grass clippings swirling around within the lower volume that need tobe expelled from a chute. However, it is worthy of note that the presentdisclosure contemplates the addition of a grass clipping discharge chutethat can be included in the deck 30 to aid in grass clipping collection,should the operator so desire.

In another example, the deck 30 is formed as a low-profile deck suchthat the depth of the deck 30 is about the same depth as thehigh-efficiency blade 46. Returning to FIG. 8 , the depth of the deck 30is represented by dimension 354 while the depth of the high-efficiencyblade is represented by dimension 356. Typical mower decks require adepth that is significantly greater than the thickness of thehigh-efficiency blade 46 in order to allow circulation of the grassclippings within the lower volume below the deck 30 until they areexpelled radially outward through a chute. However, because the grassclippings created by the high-efficiency blade 46 are directeddownwardly toward the ground and not circulated underneath the deck 30,there is no need for additional depth of the deck 30. It should beunderstood by one having ordinary skill in the art that the deck 30 canbe formed as a substantially flat deck having sufficient depth or spacebetween the high-efficiency blade 46 and the edge of the deck 30 tocomply with safety standards for mower decks and blades.

In another example, the high-efficiency lawn maintenance tool 20 can beself-propelled by using the power source 36 located on the deck 30. Inyet another example, the high-efficiency lawn maintenance tool 20 caninclude a controller 358 as shown in the schematic of FIG. 23 . Thecontroller 358 can enable the power source 36 (e.g., an electric motor)to provide infinitely variable power delivery to the high-efficiencyblade 46. The controller 358 can analyze the load on the high-efficiencyblade 46 to vary the electric power delivered to the power source 36.For example, if the controller 358 senses a relatively small magnitudeload, e.g., from short, dry grass cutting operations, the controller 358can slow the electric motor 36 by decreasing the electrical current drawfrom a battery 44 to the electric motor 36. Conversely, larger loads onthe high-efficiency blade 46 can trigger the controller 358 to provide agreater electrical current to the electric motor 36 to increase therotational speed of the electric motor 36, thereby increasing therotational speed of the high-efficiency blade 46. In another example,the controller 358 can vary both the speed and the torque delivered fromthe power source 36 to achieve an optimal grass cutting condition.

Turning to FIG. 24 , grass and vegetation cutting optimization can alsobe affected by the front-to-back tilt of some components of thehigh-efficiency lawn maintenance tool 20. FIG. 24 shows a rearward tiltof the deck 30 and the high-efficiency blade 46 to create a tilt anglerepresented by angle 360. As shown, the central axis 50 is tilted in arearward direction such that the central axis 50 is not vertical. Inother words, as the high-efficiency lawn maintenance tool 20 moves inthe direction of arrow 364, the first portion 366 (forward part) of thehigh-efficiency blade 46 to encounter a particular section of uncutgrass and/or vegetation is higher in elevation than the last portion 368(rearward part) of the high-efficiency blade 46 to cut the sameparticular section of grass and/or vegetation. This tilt can improve thecut quality, as the high-efficiency blade 46 first cuts the grass at ahigher elevation at the first portion 366 (forward part) of thehigh-efficiency blade 46 and the grass is cut again at the last portion368 (rearward part) of the high-efficiency blade 46 producing a “doublecut” effect. Dispersion of mulched clippings can also be improved withthis orientation.

This dual-cutting operation can also require more power from the powersource 36, thereby limiting battery run-time or increasing the amount ofgasoline or electrical power consumed by the high-efficiency lawnmaintenance tool 20. These competing interests can be balanced to findan optimal tilt angle 360. In one example, the tilt angle 360 of thedeck 30 and high-efficiency blade 46 is less than 3 degrees from normal.More particularly, the tilt angle 360 c an be between 1½ degrees and 2degrees. In another example, the tilt angle 360 may be optimized toproduce a cutting blade difference in elevation of about 0.15 inch toabout 0.20 inch difference between the forward part 366 and rearwardpart 368 of the cutting blades 56. FIG. 24 may show an exaggerated tiltangle 360 to emphasize the tilt orientation and effect on thehigh-efficiency blade 46.

Turning to FIG. 25 , the high-efficiency lawn maintenance tool 20 can beconfigured to include no tilt of the deck 30 and the high-efficiencyblade 46. In other words, the central axis 50 is vertical. Thisorientation can sometimes be the best compromise between energyconsumption and grass cut quality and mulched clipping dispersion.

FIG. 26 shows the high-efficiency lawn maintenance tool 20 including aforward tilt (represented by angle 370) as the high-efficiency lawnmaintenance tool 20 proceeds in the direction of arrow 364. As shown,the central axis 50 is tilted in a forward direction such that thecentral axis 50 is not vertical. In other words, as the high-efficiencylawn maintenance tool 20 moves in the direction of arrow 364, the firstportion 366 (forward part) of the high-efficiency blade 46 to encountera particular section of uncut grass and/or vegetation is lower inelevation than the last portion 368 (rearward part) of thehigh-efficiency blade 46. The forward tilt can enable a power savings,as only half of the high-efficiency blade 46 contacts the grass and/orvegetation. The tilt angle 370 can be between about 1½ degrees to about2 degrees.

The described apparatus can have numerous benefits. The high-efficiencyblade 46 can be significantly quieter than typical mower blades when inoperation. In some instances, it may be desirable to add a feature tothe high-efficiency lawn maintenance tools 20 to alert the operator thatthe high-efficiency lawn maintenance tool 20 is in operation and thehigh-efficiency blade 46 may be rotating. Some examples of alerts caninclude lights, physical movement of an additional structure, orcreation of an artificial sound.

The high-efficiency lawn maintenance tool 20 also has a relativelyhigh-efficiency thereby enabling: increased (longer) run-time of thebattery, lower cost to operate, or both. The relatively high-efficiencyof the high-efficiency lawn maintenance tool 20 can also lead to lowerfuel consumption for gasoline-powered lawn maintenance tools, such asthe one shown in FIG. 1 .

Another possible benefit to the described apparatus is a reduction inthe revolutions per minute (rpm) required for optimal grass cutting. Forexample, the relatively high-speed rotation of typical lawn mower bladescan be reduced by as much as 33%. This can enable a reduction in moweroperating noise and a reduction in operation energy needs. In oneexample, the high-efficiency lawn maintenance tool can operate at about2,200 rpm with a projected 12,000 fpm blade tip speed. This is asignificant reduction from a standard 21-inch diameter system as waspreviously discussed. In some examples, it has been shown that thecutting frequency (how many times a blade cutting surface contacts ablade of grass) can be more important than the tip speed of the mowerblade.

While preferred embodiments of the present disclosure have beendescribed, it should be understood that the present disclosure is not solimited and modifications may be made without departing from the presentdisclosure. The scope of the present disclosure is defined by theappended claims, and all devices, processes, and methods that comewithin the meaning of the claims, either literally or by equivalence,are intended to be embraced therein.

The invention claimed is:
 1. A high-efficiency blade for a lawnmaintenance tool comprising: a central axis; a mounting portion locatedon the central axis; a plurality of cutting blades, wherein each cuttingblade comprises: at least one segment; a cutting blade sharpened leadingedge, wherein the cutting blade sharpened leading edge is generallyparallel to a driven surface and the cutting blade sharpened leadingedge is configured to cut clippings from vegetation; and a plurality ofcleaning blades, wherein each cleaning blade is vertically offset fromeach of the cutting blades and is configured to mulch the associatedclippings from vegetation and reduce an associated accumulation ofclippings on an underside of an associated mower deck, and wherein theplurality of cutting blades and the plurality of cleaning blades arearranged in alternating positions around the mounting portion.
 2. Thehigh-efficiency blade according to claim 1, wherein the cutting bladeand the cleaning blade are separate arms that extend from the mountingportion.
 3. The high-efficiency blade according to claim 1, wherein thecleaning blade further comprises a cleaning blade sharpened leadingedge.
 4. The high-efficiency blade according to claim 3, wherein thecleaning blade sharpened leading edge is formed at a reverse angle. 5.The high-efficiency blade according to claim 1, wherein the cleaningblade is configured to be maintained at a relatively close distance fromthe underside of the associated mower deck.
 6. The high-efficiency bladeaccording to claim 1 comprising three cutting blades and three cleaningblades in alternating positions around the mounting portion.
 7. Thehigh-efficiency blade according to claim 1 comprising four cuttingblades and four cleaning blades in alternating positions around themounting portion.
 8. The high-efficiency blade according to claim 1,wherein the mounting portion defines a drive aperture and thehigh-efficiency blade is attached to the lawn maintenance tool with aleaf spring, the leaf spring including drive knobs configured tocooperate with the drive aperture to provide rotational power to thehigh-efficiency blade.
 9. The high-efficiency blade according to claim1, wherein high-efficiency blade further comprises: three arm sections,wherein each arm section includes one cleaning blade and one cuttingblade.
 10. A high-efficiency lawn maintenance tool comprising: a frame;a deck, wherein the deck is attached to the frame and the deck defines adownward facing space; a high-efficiency blade located within thedownward facing space, the high-efficiency blade comprising; a centralaxis; a mounting portion located on the central axis of thehigh-efficiency blade; a plurality of cutting blades, wherein eachcutting blade comprises: at least one segment; a cutting blade sharpenedleading edge, wherein the cutting blade sharpened leading edge isconfigured to cut clippings from vegetation; and a plurality of cleaningblades, wherein the each cleaning blade is vertically offset from thecutting blade, and wherein the plurality of cutting blades and theplurality of cleaning blades are arranged in alternating positionsaround the mounting portion; a power source, wherein the power source isattached to one of the frame or the deck and the power source providesrotational power to the high-efficiency blade; and a plurality of groundengaging members, wherein the ground engaging members are attached toone of the frame or the deck, wherein the deck and the high-efficiencyblade are tilted such that the central axis is not vertical.
 11. Thehigh-efficiency lawn maintenance tool according to claim 10, wherein thecentral axis is tilted rearward such that a forward part of thehigh-efficiency blade is higher than a rearward part of thehigh-efficiency blade.
 12. The high-efficiency lawn maintenance toolaccording to claim 11, wherein the central axis is tilted forward suchthat a forward part of the high-efficiency blade is lower than arearward part of the high-efficiency blade.